Patent document 1 discloses a related-art power supply unit. To improve the accuracy of output voltage, this power supply unit is capable of improving the control resolution of the output voltage, for example, by providing a plurality of voltage dividing resistors and switching the voltage dividing resistors in response to the operation mode of a load to which power is supplied.
Patent document 1: Japanese Patent Publication No. 09-218567A
However, when there are a large number of requests for switching the voltage dividing resistors, the related-art power supply unit requires a large number of voltage dividing resistors. In this case, the configuration of the power supply unit becomes complicated and an area for placing circuit components is increased. It results in a cost increase.